功能与背景
Bovine serum albumin, bovine albumin, BSA, also known as "Fraction V", is a serum albumin protein that has numerous biochemical applications; dilute antibodies, as blocking agent in ELISAs(Enzyme-Linked Immunosorbent Assay), blots, and Immunohistochemistry. It is also used as a nutrient in cell and microbial culture. In restriction digests, BSA is used to stabilize some enzymes during digestion of DNA and to prevent adhesion of the enzyme to reaction tubes and other vessels. This protein does not affect other enzymes that do not need it for stabilization. BSA is used because of its stability, its lack of effect in many biochemical reactions, and its low cost since large quantities of it can be readily purified from bovine blood, a byproduct of the cattle industry. The commercial preparations of BSA may contain IgG that may become an antigen for cross-reacting secondary antibodies; when using anti-bovine IgG, anti-goat IgG, rabbit anti-horse IgG, or anti-sheep IgG, but may occur with other antibodies that cross-react with bovine IgG as well. This will decrease antibody activity, loss of antibody stability, and/or increased background. Background may derive from sticky soluble immune complexes or from contaminating bovine IgG sticking non-specifically and attracting cross-reacting labeled secondary antibodies. Even small amounts of contaminating IgG may create these problems due to the use of high concentrations of BSA in many protocols. Our IgG and protease-free BSA should alleviate many of these problems. IgG-free BSA is supplied as a pure protein, lyophilized from distilled water.
